org.apache.commons.collections4.map
Class CaseInsensitiveMap<K,V>

java.lang.Object
  extended by java.util.AbstractMap<K,V>
      extended by org.apache.commons.collections4.map.AbstractHashedMap<K,V>
          extended by org.apache.commons.collections4.map.CaseInsensitiveMap<K,V>
All Implemented Interfaces:
Serializable, Cloneable, Map<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Put<K,V>

public class CaseInsensitiveMap<K,V>
extends AbstractHashedMap<K,V>
implements Serializable, Cloneable

A case-insensitive Map.

Before keys are added to the map or compared to other existing keys, they are converted to all lowercase in a locale-independent fashion by using information from the Unicode data file.

Null keys are supported.

The keySet() method returns all lowercase keys, or nulls.

Example:


  Map<String, String> map = new CaseInsensitiveMap<String, String>();
  map.put("One", "One");
  map.put("Two", "Two");
  map.put(null, "Three");
  map.put("one", "Four");
 
creates a CaseInsensitiveMap with three entries.
map.get(null) returns "Three" and map.get("ONE") returns "Four". The Set returned by keySet() equals {"one", "two", null}.

This map will violate the detail of various Map and map view contracts. As a general rule, don't compare this map to other maps. In particular, you can't use decorators like ListOrderedMap on it, which silently assume that these contracts are fulfilled.

Note that CaseInsensitiveMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using Collections.synchronizedMap(Map). This class may throw exceptions when accessed by concurrent threads without synchronization.

Since:
3.0
Version:
$Id: CaseInsensitiveMap.java 1477799 2013-04-30 19:56:11Z tn $
See Also:
Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.commons.collections4.map.AbstractHashedMap
AbstractHashedMap.EntrySet<K,V>, AbstractHashedMap.EntrySetIterator<K,V>, AbstractHashedMap.HashEntry<K,V>, AbstractHashedMap.HashIterator<K,V>, AbstractHashedMap.HashMapIterator<K,V>, AbstractHashedMap.KeySet<K>, AbstractHashedMap.KeySetIterator<K>, AbstractHashedMap.Values<V>, AbstractHashedMap.ValuesIterator<V>
 
Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K,V>
 
Field Summary
 
Fields inherited from class org.apache.commons.collections4.map.AbstractHashedMap
DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_THRESHOLD, GETKEY_INVALID, GETVALUE_INVALID, MAXIMUM_CAPACITY, NO_NEXT_ENTRY, NO_PREVIOUS_ENTRY, NULL, REMOVE_INVALID, SETVALUE_INVALID
 
Constructor Summary
CaseInsensitiveMap()
          Constructs a new empty map with default size and load factor.
CaseInsensitiveMap(int initialCapacity)
          Constructs a new, empty map with the specified initial capacity.
CaseInsensitiveMap(int initialCapacity, float loadFactor)
          Constructs a new, empty map with the specified initial capacity and load factor.
CaseInsensitiveMap(Map<K,V> map)
          Constructor copying elements from another map.
 
Method Summary
 CaseInsensitiveMap<K,V> clone()
          Clones the map without cloning the keys or values.
protected  Object convertKey(Object key)
          Overrides convertKey() from AbstractHashedMap to convert keys to lower case.
 
Methods inherited from class org.apache.commons.collections4.map.AbstractHashedMap
addEntry, addMapping, calculateNewCapacity, calculateThreshold, checkCapacity, clear, containsKey, containsValue, createEntry, createEntrySetIterator, createKeySetIterator, createValuesIterator, destroyEntry, doReadObject, doWriteObject, ensureCapacity, entryHashCode, entryKey, entryNext, entrySet, entryValue, equals, get, getEntry, hash, hashCode, hashIndex, init, isEmpty, isEqualKey, isEqualValue, keySet, mapIterator, put, putAll, remove, removeEntry, removeMapping, reuseEntry, size, toString, updateEntry, values
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

CaseInsensitiveMap

public CaseInsensitiveMap()
Constructs a new empty map with default size and load factor.


CaseInsensitiveMap

public CaseInsensitiveMap(int initialCapacity)
Constructs a new, empty map with the specified initial capacity.

Parameters:
initialCapacity - the initial capacity
Throws:
IllegalArgumentException - if the initial capacity is negative

CaseInsensitiveMap

public CaseInsensitiveMap(int initialCapacity,
                          float loadFactor)
Constructs a new, empty map with the specified initial capacity and load factor.

Parameters:
initialCapacity - the initial capacity
loadFactor - the load factor
Throws:
IllegalArgumentException - if the initial capacity is negative
IllegalArgumentException - if the load factor is less than zero

CaseInsensitiveMap

public CaseInsensitiveMap(Map<K,V> map)
Constructor copying elements from another map.

Keys will be converted to lower case strings, which may cause some entries to be removed (if string representation of keys differ only by character case).

Parameters:
map - the map to copy
Throws:
NullPointerException - if the map is null
Method Detail

convertKey

protected Object convertKey(Object key)
Overrides convertKey() from AbstractHashedMap to convert keys to lower case.

Returns AbstractHashedMap.NULL if key is null.

Overrides:
convertKey in class AbstractHashedMap<K,V>
Parameters:
key - the key convert
Returns:
the converted key

clone

public CaseInsensitiveMap<K,V> clone()
Clones the map without cloning the keys or values.

Overrides:
clone in class AbstractHashedMap<K,V>
Returns:
a shallow clone


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